Microtome



July 29, 1958 c. E. soDERQUlsT, JR 2,844,993

MIcRoToME Filed March 29. 1955 y 2 Sheets-Sheet 1 ne. a

I N VEN TOR.

July 29,195.8 c. E.soDr-:RQU1sT,JR Y 2,844,993

MIcRoToME 2 Sheets-Sheet 2 Filed March 29, 1955 FIG. 4

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INVENTOR.

United States Patent Oliice 2,844,993. Patented July 29, 1958 MICRoToMECharles E. Soderquist, Jr., Chicago Heights, Ill., assignor, by mesneassignments, to Instrument & Development Products Co., a corporation ofIllinois Application March 29, 1955, Serial No. 497,670 2 Claims. (Cl.38-40) The invention herein described is a new type of ultra-microtome,designed to give sections of suicient thinness to allow them to be usedin electron microscopy.

Until the present time, most feed mechanisms for such devices dependedupon various types of advancing motions which were lubricated by oilfilms. These lms are extremely variable and when sections to be cut areof the range of size where variations in oil films are greater than thethickness of the cut sections, serial sections of uniform size areimpossible to obtain.

The development of this microtome has two basic aims;

(a) to eliminate oil films on the moving parts of the machine.

(b) to achieve a great reduction in mechanical feed.

The accompanying drawings are:

Figure 1, a plan view of the microtome;

Figure 2, an elevation of same;

Figure 3, a detailed isometric view of the leaf spring mount;

Figure 4, a vertical section assembly on line 4, 4.

The microtome feed tube assembly as shown in Figure 4, consists of metaltube 18, rigidly held and supported in block 19, by the pressure of nut24, being pushed by the plate 20, which in turn is held in place byscrews 21. The knurled feed screw 17, rotates in nut 24, and bears uponthrust bearing 22. This action compresses spring 23, which stresses tube18. When tube 18 is stressed, its deformation is proportional to thestress as long as the stresses applied are within the elastic limit ofthe material. This holds true for extremely small increments as well aslarge ones.

By using various pitched threads and nuts, and springs of differentrates, a great variation in feed is possible. It is also possible to usehydraulic cylinder for applying the load to the spring 23. However, forincrements of the size for which this machine was designed, the spring23, can be compressed readily enough with screw 17.

The whole feed tube assembly Fig. 4, is mounted upon two leaf springs 1,as shown in Fig. 3. These springs avoid the use of conventional pivotswith the associated play in such pivots. The leaf springs 1, are clampedto the feed tube support block 19, by blocks 2, held in place thru themain feed tube by screws 3. The other ends of the leaf springs 1 areclamped to upright supports 4 by blocks 6, held in place by screws 5.

The normal equilibrium position of the leaf springs 1 holds the tube 18,horizontal. When a section is to be cut, the specimen 11 is held tocollet 16. The knurled screw 17 is rotated the desired amount whichcauses tube 18 to elongate as per the description above.

By ypressing down on the knurled collet 16 the specimen 11 describes anarc with the leaf springs 1 acting as pivots. This -arc movement passesspecimen 11 over the edge of the knife blade 10 causing a section tobecut off. When the downward force is removed, the leaf springs 1 returnthe tube assembly to the horizontal position again.

Uprights 4, are part of base 25. Coarse knife feed block 14 and lineknife feed block 12 are standard dovetail type ways with adjustingscrews 1K5, and 13. Knife blade 10 is held by blade holder 9 and clamp 8and tightening screw 7. Items 12, 13, 14, 15, and 7, 8, 9, 10 arestandard machine details and are not claimed as part of the invention.

Therefore, I claim:

1. A micro-positioning assembly comprising a base, a tube mounted on thebase and having on one end thereof a specimen-holding member and on theother end thereof a threaded member, a coiled spring within the tube,and a manually rotatable second threaded member engaging the firstthreaded member and abutting against one end of the spring to compressthe spring, whereby the specimenholding member is varied in position inmicroscopic amounts with respect to the base by the stress, suchvariation being linear with the rotation of the threaded member. l.'

2. A micro-positioning assembly comprising a base, an elongated membermounted on the base and having on one end thereof a specimen-holdingmember and on the other end thereof a threaded member, a manuallyrotatable second threaded member engaging the rst threaded member and aspring acting between the second threaded member and thespecimen-holding member, whereby the specimen-holding member is variedin position in microscopic amounts with respect to the base by thestress, such variation being linear with the rotation of the threadedmember.

References Cited in the le of this patent UNITED STATES PATENTS2,357,356 Petty sept. 5, 1944 2,383,997 Sweet Sept. 4, 1945 2,563,423sammhrakis Aug. 7, 1951 2,651,236 Kahler Sept. 8, 1953 2,739,507 cockset a1. Mar. 27, 1956 2,753,761 Hillier July 1o, 1956 FOREIGN PATENTS1,065,788 'France Jan. 13, 1954

